Pipe joint



May 24, 1932. J. H. Mc v JR 1,859,311

PIPE JOINT Filed June 1, 1926 I H mqfilYVENTOR.

A TTORNE Y.

Patented May 24, 1932 i UNITED STATES. PATENT OFFICE JOSEPH H. McE'VOY, JR, F HOUSTON, TEXAS PIPE JOINT Application filed June 1, 1926. Serial No. 112,736;

My invention relates to the construction have found that if the sections are separated of pipe joints for use particularly in deep by a thin layer of electrically insulating mawell operations. terial, the electrolytic action may be largely In equipping an oil well or a deep water avoided. Y well for production, it is common to provide It is an object therefore to provide a joint a casing or liner of iron or steel ipe extend or coupling for pipe so constructed and ining from the surface to the pro ucing strasulated that electrolytic disintegration of tum; and to connect, at the lower end of the the pipe at the ends of adjacent sections will pipe, a strainer or well screen which may be be overcome to such an extent that the life 10 of a different material from that of the pipe. of the joint will be indefinitely prolonged. The strainer may be of perforated plpe Referring to the drawings herewith, Ihave Wound with screen wire, or may have strainer shown in Fig. 1 a central longitudinal secbuttons in the perforations, or may assume tion through a pipe joint illustrating the apother forms. But the strainer may be of a 'plication thereto-of my invention. Fig. 2 is 15 better and different composition of steel from a side elevation of the joint shown in Fig. 1. that of the pipe to which it is connected, or It is to be understood that my invention is may be of brass, or some different alloy applicable to pipes for different uses which adapted to resist the action of moving sand are adapted to be submerged in liquids, and and the corrosion of acids or other fluids in particularly to pipes wherein some of the 20 the well. sections of the said pipes are of difierent It has been found that, when metals of composition asto metallic constituents from different composition, or of different solu .the other'adjacent sections. Thisdifference tion pressures, are submerged in the liquid occurs particularly in oil well operations in the well, a difference of electrical potenwhere the strainer employed is of a different 25 tials is set up causing electrolysis between quality of steel or is made up of brass, or the different pipe sections. Metal from a other similar metal. In the drawings,Ihave pipe of one composition is eaten away and shown my joint as applied to two sections of carried away in the electrolyte. This is due pipe-1 and 2-the adjacent ends of which to the presence of foreign substances in the are threaded with a coarse thread 3. A cou- 30 liquid in the well forming an electrolyte. pling or collar 4 is provided for connecting Sulphur, salt water, and similar elements in together the ends ofthe adj acentsections of the liquid serve to produce such a result. pipe and said collar is threaded to engage The usual cause of this electrolytic action with the threads upon the pipe. I have is that the pipe sections form electrodes of shown the threads'as being formed upon a 5 large surface areas so that a strong galvanic tapered surface, as this is the most common 8 current is set up flowing from one section to method of forming the threads upon the another of different potential. It has been pipe, the advantage being that thepip'e' secfound that the metal of the pipe section adtions are connected and released from each jacent the strainer, being of different comother by a fewer number of turns of the 0 position from the strainer, will act as one coupling. i. electrode and the strainer as the other, and Under ordinary circumstances where the that a marked disintegration of one or the section'2 is made of a different metal from other of the metals at the joint will occur, that in the section '1, the electrolytic action, soon acting to cause holes in the pipe or which has been. previously described, is set 45 strainer at the joint destroying the connecup. I'haveIprlovided against the disintegra- I tion between them and allowing the entrance tion of the metals through this action by to the pipe of sand and other sediment. Y forming upon theends of the pipe sections a While a strong electric current is produced thin layer of electrically insulating matein this way, the difference of potential berial 5., This material may beof various tween adjacent sections is not great and I kinds; it may be of some treated fabric combsition or it may even be a coating of some insulating materlal applied thereto with a brush and allowed to set. It is contemplated that the coating of whatever material is em-' shown the insulating material as applied to both sections of pipe, it is to be understood that this idea is only optional. As will be noted, the insulating coat is extended slightly beyond the ends of the coupling so as torovide against the passage of the current rom the pipe 1 above the end of the insulating sleeve around to the adjacent end of th coupling 4. I have also shown the insula 'ng material as being placed somewhat In re thickly at the central point 6 upon the coupling to fit between the adjacent ends of the pipe. This has the advantage of effectively separating the pipe ends and preventing the passage of electric current from one section to the other.

It is believed that the operation ,of'the invention will be clear from the description already given. It is the substance of the invention to provide an insulation between the adjacent ends of pipe sections of different material and particularly the invention is designed for use in the coupling joining the .well pipe to the upper end of the well screen.

It is necessary in many installations to form the screen of much more expensive and costly material than that employed in the construction of the pipe. The use of a more expensive' and durable material in the well screen,

however, is largely overcome as an advantage where the connection between the pipe and the screen is soon disintegrated and worn. By the use of this type of joint described and ing, and a thin layer of dielectric placed between said coupling and said pipe and tubing, the thickness of said dielectric bein less than the depth of the threads on sai coupling, pipe or tubing.

3. A connection adapted to prevent electrolysis of adjacent pipe ends of diflerent electrolytic composition including a. coupling, mterengaging threads on said pi and said cou ling, a thin layer of dielectric covering sai threads and adapted to prevent an electrical contact between said ends and said coupling, and a dielectric ring abutting the adjacent pipe ends.

In testimony whereof I hereunto .aifix my 30 signature this 28 dag lof May A. D. 1926.

- JOSEP H. McEvoY, JR.

shown herein; the connection between the pipe and the screen may be made durable andlasting and the life of the screen may be extended for a long period of time.

Having thus described my invention, what I claim as new and desire to protect by Letters Patent is: v

1. An electrically insulated pipe joint compris ng, threaded pipe members, a threaded cou ling member, a coating of electricalinsula ing material of less thickness than the dept of the threads upon at least. one of said members, and a ringof insulating material between the ends of said pipe members.

2. A connection between a section of strainer pipe and well tubing formed of different electrolytic compositions, comprising a coupling adapted for threaded connection to ad acent ends of said-pipe and said tub- 

